Device for actuating a friction clutch with automatic adjustment

ABSTRACT

A device for actuating a friction clutch with automatic adjustment. An actuating movement for engaging and disengaging the clutch is transmitted to a pressing component. The adjusting device includes a sensing component that is biased in the direction of an adjusting movement and compensates for sensing play that occurs as a result of wear when the clutch is engaged, and that compensates for play that occurs when the clutch is disengaged after compensation of the sensing play in the movement transmission between the actuating component and the transmission component. When the clutch is engaged and wear is present, the sensing component moves out of contact against a spring component which, when the clutch is engaged and wear is present, comes into contact against a stop before the fully engaged state of the clutch is reached.

The invention relates to a device for actuating a friction clutch with automatic adjustment.

From DE 10 2004 019 809 A1, on which the preamble of patent claim 1 is based, a twin clutch assembly with automatic adjustment is known. The adjustment devices, which are associated with each particular clutch, are identical and respectively include a leaf spring shaped capture component, which is supported at a force transmission element 44 through a sensing or arresting element and through adjustment elements disposed parallel thereto, wherein said force transmission element is engaged by the transmission component. It is particular for the described adjustment devices that the sensing component, as well as the adjustment component, are disposed in the force transmission path from the leaf spring shaped capture element, actuated by the actuation element, to the force transmission element, so that the adjustment movements, which depend on the deformation or tilting of the leaf spring shaped capture element are coupled in a complex manner.

It is the object of the invention to improve a device of said type, so that safe wear compensation is provided with a simple configuration.

According to the invention said object is accomplished by a device for actuating a friction clutch with automatic adjustment, which comprises an actuation component whose actuation movement is transmitted to a transmission component through an adjustment device, wherein an actuation movement for engaging and disengaging the clutch can be transmitted by said transmission component to a pressing component, wherein the adjustment device comprises a sensing component, which is preloaded in the direction of an adjustment movement, wherein the sensing component compensates a sensing clearance which occurs due to wear when the clutch is disengaged, and wherein the adjustment device comprises an adjustment component which is preloaded in the direction of an adjustment movement, which adjustment component compensates a clearance which occurs in the transmission of the movement between the actuation component and the transmission component when the clutch is disengaged after the sensing clearance has been compensated, in which device the sensing component is not included in the transmission of the movement from the actuation component to the transmission component and wherein the sensing component is disposed, so that it comes clear by the amount of the sensing clearance from a contact with a spring component, when the clutch is engaged and wear is present, which spring component contacts a stop when the clutch is being engaged and wear is present, before the clutch is completely engaged.

According to the invention a spring component is deformed by reaching a stop when the clutch is being engaged and wear is present, which creates a sensing clearance between the spring component and the sensing component, which is compensated by adjusting the sensing component. This changes the resting position, which the actuation component assumes when the clutch is being disengaged, so that a clearance, which occurs in the movement transmission between the actuation component and transmission component, is compensated by adjusting the adjustment component. The sensing component, as well as the adjustment component, is free of force under the respective clearances, so that their adjustment movements are being safely performed.

In one embodiment of the device according to the invention, the sensing component is disposed between the transmission component and the spring component, wherein the spring component, which is disposed at the transmission component, thereby comes into contact with a stop fixated at the housing when the clutch is being engaged, and the spring component comes clear from the sensing component when the required wear compensation is performed, so that the sensing clearance can be compensated by adjusting the sensing component.

Preferably, the sensing component contacts another stop, which is fixated to the housing, with its side facing away from the sensing component when the clutch is disengaged.

Preferably, the adjustment component is disposed between the actuation component and the transmission component, wherein a clearance occurs in the movement transmission between the actuation component and the transmission component after an adjustment of the sensing component, when the clutch is engaged and the actuation component is in its resting position, wherein said clearance can be compensated by adjusting the adjustment component.

In said embodiment of the device according to the invention, the adjustment component can be a lever, which is supported at a bearing fixated at the housing which lever imparts a pressing force through the adjustment component onto the transmission component in order to engage the clutch.

In another embodiment of the device according to the invention the actuation component is supported through the adjustment component at a clutch housing and the sensing component contacts the actuation component at a distance from the adjustment component on the same side as the adjustment component and furthermore contacts the spring component fixated to the housing and contacts the housing, wherein the assembly is configured, so that the sensing component comes clear from the actuation component during its engagement movement and the spring component comes clear from the sensing component by contacting a stop, which is configured at the transmission component, when the clutch is engaged and wear has occurred, so that the sensing component is adjustable for adjusting the sensing clearance.

The sensing component and the adjustment component are preferably configured by substantially annular components, which surround the axis of the clutch. The faces of the annular components are configured and interact with the opposed surfaces of the components interacting with said annular components, so that their effective axial length is a function of their angular position with reference to a rotation about the axis of the clutch.

The invention can be used for all types of wearing friction clutches. The device according to the invention, due to its simple and compact configuration, is suitable in particular for actuating a twin clutch assembly disposed in a parallel variable speed transmission, in particular for the start-up clutch of a dry twin clutch assembly. The adjustment device respectively adjusts the entire occurring wear; this means not only the wear of the friction liners, but also the wear at the contact points between the actuation members.

The invention is subsequently described in more detail in an exemplary manner with reference to schematic drawing figures, wherein:

FIG. 1 shows a sectional view of components of a friction clutch in a plane including the axis of the clutch;

FIG. 2 shows detail A of FIG. 1;

FIG. 3 shows six different actuation states of components in order to illustrate the adjustment process; and

FIG. 4-6 show figures corresponding to FIGS. 1-3 for illustrating another embodiment of the clutch according to the invention.

According to FIG. 1, a clutch whose axis is designated with X-X in FIG. 1 comprises a housing 10 of which only a cover is shown. An actuation lever 14 is supported by a wire ring bearing 12 at the housing 10, wherein said actuation lever actuates a pull anchor 18 through components of an adjustment device designated overall with 16, which is rigidly connected with a pressing plate 20. By moving the pressing plate 20 upward according to FIG. 1, friction liners 22 of a clutch disc 24 come in friction contact with the press plate 20 and with an intermediary plate 26 mounted to the housing.

Through another actuation lever 28 another pressing plate 30 can be moved downward according to FIG. 1, so that another clutch disc 32 comes in frictional engagement with the intermediary plate 26 or with the pressing plate 30.

Besides the two clutch discs 24 and 32, all components mentioned supra can be connected torque proof with the output shaft of an internal combustion engine. The clutch disc 24 can be connected torque proof with a first clutch shaft, which is not shown and which is disposed within a hollow second clutch shaft, to which the clutch disc 32 can be connected torque proof. The actuation levers 14 and 28 can be actuated by disengagement bearings, which are supported on the outer clutch shaft which is not shown.

The configuration and the function of the twin clutch are generally known and are therefore not described.

It is appreciated that the components visibly disposed in the sectional view only on both sides of the axis X-X, are substantially disc- or ring shaped components which surround the axis X-X.

Subsequently, the adjustment device according to the invention is described with reference to FIG. 2, which shows detail A of FIG. 1 in an enlarged scale.

It is evident that the movement transmission is performed by the actuation lever 14, e.g. an annular disc with invert protruding spring elastic tongues onto the pull anchor 18 which is used as a transmission component for transmitting the movement of the lever 14 onto a press plate 20 through an adjustment ring 34, whose axial face, which contacts the pull anchor 18, is configured as a ramp and interacts with respective ramp surfaces 36 configured at the pull anchor. The adjustment ring 34 is preloaded in circumferential direction relative to the pull anchor 18 by springs acting in circumferential direction which are not shown, so that the adjustment ring 34 rotates relative to the pull anchor 18 and relative to the actuation lever 14, when the distance between the pull anchor 18 and the actuation lever is increased, so that zero clearance is maintained in the movement transmission from the actuation lever 14 to the pull anchor 18 through relative movement between the ramp surfaces.

At the housing 10 furthermore a lower stop 38 is provided, at which a spring component 40, which is mounted to the pull anchor 18 and configured as a tension spring, contacts in the illustrated disengaged position of the clutch. A sensing ring 42 is disposed between the spring component 40 and the pull anchor 18, which is preloaded in a similar manner as the adjustment ring 34 by springs, which are not shown, for a rotation circumferential direction, wherein said springs are supported at the sensing ring 42 and at the pull anchor 18. The contact of the sensing ring 42 at the pull anchor 18 is performed by ramp surfaces 44.

According to the figure another stop 46 which is fixated to the housing is provided above the stop 38 and the function of said stop 46 will be described infra.

According to FIG. 3 an adjustment process with five states a)-f) is described infra:

In state a), the clutch is disengaged, this means the actuation lever 14 is mostly pivoted counterclockwise and the pull anchor according to the figure is in its lowest position, in which the spring component 40 contacts the lower stop 38.

In state b), the clutch is being engaged by pivoting the actuation lever 14 clockwise, wherein the full contact pressure of the pressing plate at the clutch disc is not yet reached and the spring component 40, which has come clear from the lower stop 38, follows the movement of the pull anchor 18. A state is illustrated in which the spring component 40 comes into contact with the upper stop 46.

When the actuation lever 14 is actuated further for full engagement of the clutch, the spring component 40 is deformed through contact at the upper stop 46, so that the sensing ring 42 comes clear from the contact at the spring component 40 and becomes force free. The amount, by which the sensing ring 42 clears the spring component 40, depends on the wear of the clutch and it becomes larger with increasing wear.

The clearance which occurs between the sensing ring 42 and the spring component 40 is reduced in the state d) by adjusting the sensing ring which is free of contact forces and thus moveable with little friction, so that the clearance is safely compensated and the state d) in which the sensing ring 42 contacts the spring component 40 and the pull anchor 18 without clearance, is the fully engaged state of the clutch after the sensing clearance or the sensing gap 48 have been compensated.

When the clutch is disengaged (state e)), the spring component 40 in turn comes in contact with the lower stop 38, wherein the distance between the pull anchor 18 and the lower stop 38 is increased due to the adjusted sensing ring 42, so that when the actuation lever 14 is in disengaged position (same position as in state a)), a clearance between the adjustment ring 34 and the actuation lever 14 occurs, which is compensated by adjusting the adjustment ring 34 since hardly any forces are present, so that the state f) corresponds to the state a), in which no clearance exists at the contact surfaces of the rings, but the pull anchor 18 is adjusted upward overall in order to compensate wear according to the figure.

FIG. 4 shows an embodiment of a clutch, which is revised relative to FIG. 1 with respect to the adjustment device and the support of the actuation lever at the housing.

According to FIGS. 4 and 5, the actuation lever 14 is not supported at the housing 10 by a wire ring bearing 12 in this embodiment, like in FIG. 1, but it is supported by an adjustment ring 64, which contacts the housing 10 through ramp surfaces 66 and which is preloaded by springs which are not shown relative to the housing 10 for a rotation in circumferential direction.

At the free end of the lever 14, opposite to the contact point between the between the lever 14 and the pull anchor 18, a sensing ring 72 is disposed which contacts the lower side of the actuation lever 14 with its outside and which contacts the housing 10 with its inside through ramp surfaces. At the housing a spring component 76 is mounted, which is configured as a tension spring which interacts with the sensing ring 72 and with a protrusion of the pull anchor 18, which forms a stop 78 as described infra.

The function of the assembly according to FIGS. 4 and 5 is described in a similar manner as the function of the assembly according to FIGS. 1 and 2 with reference to six states a) through f) according to FIG. 6.

State a) illustrates the clutch in disengaged state. The actuation lever 14 which is in disengagement position contacts the adjustment ring 64 and it is forced by the pull anchor 18, which is disposed in disengagement position of the clutch, to contact the sensing ring 72 with its free end, wherein said sensing ring is supported at the housing 10.

In order to engage the clutch, the actuation lever 14 is pivoted clockwise about its support location on the adjustment ring 64 (state b)). Its free end thus clears the sensing ring 72, whose rotatability is restricted, however, by the contact at the spring component 76.

When wear has occurred in the clutch, the actuation lever 14 can continue to move from the position according to b), in which the pull anchor 18 has moved upward far enough, so that the stop 78 contacts the spring component 76, so that the spring component 76 is moved upward from the stop 78 and comes clear from the sensing ring 72, which creates a sensing gap 80, which can be compensated by rotating the preloaded sensing ring 72 (state d)), so that in turn no clearance exists between the sensing ring 72 and the spring component 76, which is deformed upward according to the figure now.

When the clutch is subsequently disengaged and the actuation lever 14 is moved back into its disengagement position (state e)), which brings the free end of the lever into contact with the sensing ring 72, which is rotated relative to the state a), the adjustment ring 64 become force free, so that it can be readjusted due to its preload in circumferential direction (state f) and the disengaged state of the clutch is reached without clearance and with wear compensation.

The invention which is described with reference to 2 embodiments facilitates reliable wear adjustment, wherein not only the wear of friction liners, but also the wear in the actuation system of the clutch is compensated. In principle, the adjustment can also compensate tolerances between transmission and clutch, so that aligning the clutch disk in the transmission factory can be avoided. The described wear adjustment is not sensitive to the sagging of springs and dynamic influences.

REFERENCE NUMERAL LIST

10 Housing

12 Wire Ring Bearing

14 Actuation Lever

16 Adjustment Device

18 Pull Anchor

20 Plate

22 Friction Liners

24 Clutch Disc

26 Intermediary Plate

28 Actuation Lever

30 Pressing Plate

32 Clutch Disc

34 Adjustment Ring

36 Ramp Surface

38 Lower Stop

40 Spring Component

42 Sensing Ring

44 Ramp Surface

46 Stop

48 Sensing Clearance

56 Adjustment Device

64 Adjustment Ring

66 Ramp Surface

72 Sensing Ring

74 Ramp Surface

76 Spring Component

78 Stop

80 Sensing Gap 

1. A device for actuating a friction clutch with automatic adjustment, which device comprises an actuation component, whose actuation movement is transmitted through an adjustment device to a transmission component by means of which the actuation movement for engaging and disengaging the clutch can be transmitted to a pressing component, wherein the adjustment device comprises a sensing component, which is preloaded in the direction of an adjustment movement, which sensing component compensates a sensing clearance, which occurs due to wear when the clutch is engaged, and which comprises a adjustment component which is preloaded in the direction of an adjustment movement, which adjustment component compensates a clearance which occurs in the movement transmission between the actuation component and the transmission component when the clutch is disengaged and after the sensing clearance has been compensated, wherein the sensing component is not included in the movement transmission from the actuation component to the transmission component and is disposed so that it moves clear from a stop at a spring component by the amount of the sensing clearance when the clutch is engaged and wear exists, which spring component contacts a stop when the clutch is being engaged and wear exists, before the fully engaged state of the clutch is reached.
 2. A device according to claim 1, wherein the sensing component is disposed between the transmission component and the spring component, which spring component is disposed at the transmission component and thereby comes in contact with a stop fixated to the housing when the clutch is being engaged, and which comes clear from the sensing component, when wear compensation is required, so that the sensing clearance can be compensated by adjusting the sensing component.
 3. A device according to claim 2, wherein the spring component contacts another stop, fixated to the housing, with its side facing away from the sensing component when the clutch is disengaged.
 4. A device according to claim 2, wherein the sensing component is disposed between the actuation component and the transmission component, wherein a clearance in the movement transmission between the actuation component and the transmission component occurs after an adjustment of the sensing component, when the clutch is engaged and the actuation component is in its resting position, which clearance can be compensated by adjusting the adjustment component.
 5. A device according to claim 1, wherein the actuation component is a lever, which is supported at a bearing, which is fixated to the housing, which lever imparts a pressing force for engaging the clutch through the adjustment component upon the transmission component.
 6. A device according to claim 1, wherein the actuation component is supported through the adjustment component at a clutch housing and the sensing component contacts the actuation component at a distance from the adjustment component on the same side as the adjustment component and furthermore contacts the spring component, which is fixated to the housing, and the housing, wherein the assembly is configured so that the sensing component comes clear from the actuation component during its engagement movement and the spring component comes clear from the sensing component when the clutch is engaged and wear has occurred through the spring component contacting a stop, which is configured at the transmission component, so that the sensing component is adjustable for compensating the sensing clearance.
 7. A device according to claim 1, wherein the sensing component and the adjustment component are formed by overall annular components, which surround the axis of the clutch and whose front faces are configured and interact with opposite surfaces of the components interacting with them, so that their effective axial length is a function of their rotation position with reference to a rotation about the axis of the clutch.
 8. A device according to claim 1, wherein the device is provided for actuating a clutch of a parallel variable speed transmission of a twin clutch assembly. 